The present invention relates to an analog type of electronic timepiece, i.e. an electronic timepiece provided with analog display means such as time indicating hands driven by an electro-mechanical transducer, which is provided with an alarm function, and in particular to an analog electronic timepiece which is provided with means whereby the alarm time can be set to a desired value easily and accurately.
At present, various types of digital or combined analog/digital electronic timepieces are available which can provide an alarm function having a very high degree of accuracy, i.e. such that an alarm time can be set to a precision of the order of a few seconds. However it has proven much more difficult to provide such a highly accurate alarm function in an analog electronic timepiece. Although there are on the market at present a few analog electronic timepieces which provide an alarm function, the accuracy is in general relatively poor, by comparison with that available from digital types of timepiece. One of the reasons for this is that it is difficult to set an alarm time accurately and easily, with such a prior art type of analog electronic timepiece. This setting is generally performed by rotating an external operating member, such as a timepiece crown, and thereby generating signal pulses which are applied to drive an electro-mechanical transducer (usually a miniature stepping motor) to successively advance the hands to the desired alarm time setting. Usually, during the normal current time display state of such an analog electronic timepiece, the hands are advanced by the stepping motor in steps of less than one minute in amplitude, e.g. in steps of 20 seconds or 30 seconds. One of the main reasons for this is that the operation of such a miniature stepping motor is made more efficient and stable as the amplitude of each drive step is reduced, in other words less energy is required to advance the motor from one position to the next as the amplitude of each step is reduced, and in addition a greater stability of the stepping motor rotor position is attained, with respect to external disturbing influences, as the amplitude of each step is reduced. For this reason, when the user performs setting of an alarm time, by rotation of an external operating member, the stepping motor will advance the hands in steps of less than one minute at a time, e.g. 10 seconds, 20 seconds, 30 seconds, in response to each pulse generated by actuation of the external actuating member. Thus, it is difficult for the user to set the minutes hand of the timepiece precisely at a desired minutes units position, i.e. positioned precisely at one of the minutes graduations on the timepiece dial. Thus, for example, if the user attempts to set in a time of 8:00 (i.e. 8 o-clock) as the alarm time, then if the timepiece is slightly tilted with respect to the viewing position of the user when setting is carried out, a time of 7:59:30 (i.e. 7 hours, 59 minutes, 30 seconds) may be actually set as the alarm time, or a time of 8:00:30 (i.e. 8 hours, zero minutes, 30 seconds). There are some conditions in which it is required to generate an alarm signal at a precisely determined time, and thus, with such a prior art analog electronic timepiece the alarm signal will be emitted at an instant which is slightly delayed or advanced with respect to the desired alarm time, and this will give the user the impression that the timepiece is inaccurate in its time measurement capabilities. However in fact this inaccuracy is due to the fact that it is difficult for the user to set the alarm time to the desired value with a high degree of precision.
There is therefore a requirement for an analog electronic timepiece which would overcome the problem outlined above, and to enable the user to easily and conveniently set a desired alarm time, without having to pay a great deal of care to the setting operation.